oj.uz

Submission #339212

# Submission time Handle Problem Language Result Execution time Memory
339212 2020-12-24T20:38:27 Z cheissmart Cheerleaders (info1cup20_cheerleaders) C++14
100 / 100
 1641 ms 68972 KB 
// #include <bits/stdc++.h>
#include <vector>
#include <algorithm>
#include <random>
#include <iostream>
#include <ctime>
#pragma GCC optimize("Ofast", "unroll-loops", "no-stack-protector")
#define IO_OP std::ios::sync_with_stdio(0); std::cin.tie(0);
#define F first
#define S second
#define V vector
#define PB push_back
#define MP make_pair
#define EB emplace_back
#define ALL(v) (v).begin(), (v).end()
#define debug(x) cerr << "Line(" << __LINE__ << ") -> " << #x << " is " << x << endl
 
using namespace std;
 
typedef long long ll;
typedef pair<int, int> pi;
typedef V<int> vi;
 
const int INF = 1e9 + 7, N = 17;
 
int a[1 << N];
vi who[N][1 << N];
 
signed main()
{
	IO_OP;
 
	int n;
	cin >> n;
// n = 17;
	if(n == 0){
		cout << 0 << endl;
		cout << endl;
		return 0;
	}
	for(int i = 0; i < (1 << n); i++) {
		int x;
		cin >> x;
// x = i;
		a[x] = i;
	}
// mt19937 rng(time(0));
// shuffle(a, a + (1 << n), rng);
 
	auto shift_right = [&]() {
		cout << 2;
	};
	auto flip_bit = [&](int bit) {
		for(int i = 0; i < bit + 1; i++) shift_right();
		cout << 1;
		for(int i = 0; i < n - bit - 1; i++) shift_right();
	};
	auto xor_val = [&](int val) {
		for(int i = 0; i < n; i++) if(val >> i & 1)
			flip_bit(i);
	};
	ll best_inv = 1e18, best_shift = 0, best_xor = 0;	
	for(int i = 0; i < n; i++)
		for(int j = 0; j < (1 << (n - i)); j++)
			who[i][j].reserve(1 << i);
	for(int shift = 0; shift < n; shift++) {
		for(int i = 0; i < n; i++)
			for(int j = 0; j < (1 << (n - i)); j++)
				who[i][j].clear();
		for(int j = 0; j < (1 << n); j++)
			for(int i = 0; i < n; i++)
				who[i][a[j] >> i].PB(j);
		auto count_inv = [&](vi& a, vi& b) {
			ll ans = 0;
			for(int i = 0, j = 0; i < a.size(); i++) {
				while(j < b.size() && b[j] < a[i]) j++;
				ans += j;
			}
			return ans;
		};
		ll val = 0, inv = 0;
		for(int i = 0; i < n; i++) {
			ll one = 0, zero = 0;
			for(int prefix = 0; prefix < (1 << (n - i)); prefix += 2) {
				int mask1 = prefix, mask2 = prefix + 1;
				ll cur_zero = count_inv(who[i][mask1], who[i][mask2]);
				// ll cur_one = count_inv(who[mask2][i], who[mask1][i]);
				ll cur_one = (1LL << i << i) - cur_zero; // const opt
				one += cur_one, zero += cur_zero;
			}
			if(one < zero) val |= 1 << i;
			inv += min(one, zero);
			if(inv > best_inv) break; // const opt
		}
		if(inv < best_inv) {
			best_inv = inv;
			best_shift = shift;
			best_xor = val;
		}
		for(int i = 0; i < (1 << n); i++)
			a[i] = (a[i] >> 1) | ((a[i] & 1) << (n - 1)); // shift right
	}
	cout << best_inv << endl;
	for(int i = 0; i < best_shift; i++) shift_right();
	xor_val(best_xor);
	cout << endl;
}

Compilation message

cheerleaders.cpp: In lambda function:
cheerleaders.cpp:75:28: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   75 |    for(int i = 0, j = 0; i < a.size(); i++) {
      |                          ~~^~~~~~~~~~
cheerleaders.cpp:76:13: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   76 |     while(j < b.size() && b[j] < a[i]) j++;
      |           ~~^~~~~~~~~~

Subtask #1
16.0 / 16.0

# Verdict Execution time Memory Grader output
1 Correct 34 ms 52716 KB Correct!
2 Correct 35 ms 52716 KB Correct!
3 Correct 35 ms 52716 KB Correct!
4 Correct 34 ms 52716 KB Correct!

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 35 ms 52736 KB Correct!
2 Correct 35 ms 52716 KB Correct!
3 Correct 34 ms 52716 KB Correct!
4 Correct 36 ms 52716 KB Correct!

Subtask #3
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 39 ms 52844 KB Correct!
2 Correct 40 ms 52844 KB Correct!
3 Correct 40 ms 52972 KB Correct!
4 Correct 40 ms 52844 KB Correct!

Subtask #4
21.0 / 21.0

# Verdict Execution time Memory Grader output
1 Correct 137 ms 56300 KB Correct!
2 Correct 146 ms 56300 KB Correct!
3 Correct 290 ms 60268 KB Correct!

Subtask #5
28.0 / 28.0

# Verdict Execution time Memory Grader output
1 Correct 755 ms 68204 KB Correct!
2 Correct 778 ms 68332 KB Correct!
3 Correct 1624 ms 68204 KB Correct!
4 Correct 1588 ms 68332 KB Correct!
5 Correct 1641 ms 68972 KB Correct!